More Discrete Probability Distributions

Which of the following is NOT an assumption of the Binomial distribution?

• All trials must be independent.

• Each trial must be classified as a success or a failure.

• The random variable is the count of failures in the trials.

• The number of successes in the trials is counted.

Is the distribution below a probability distribution? Why or why not?

• Yes. All P(x) values are between 0 and 1, and ∑P(x) = 1

• No, not all P(x) values are between 0 and 1.

• No, ∑P(x) ≠ 1.

• Yes, ∑P(x) ≠ 1

An algebra 2 test has 25 multiple choice questions with five choices and one correct answer each. If we just randomly guess on each of the 25 questions, what is the probability that you get exactly 12 questions correct?

• 0.9988

• 0.0012

• 0.4587

• 0.0117

The American Red Cross says that about 11% of the U.S. population has Type B blood. A blood drive is being held at your school. What is the probability that at least 3 of the first 10 blood donors has Type B blood?

• 0.9822

• 0.9116

• 0.3030

• 0.0884

Bob is taking a 50 question test. They have a 60 % probability of getting any one question correct. WHICH IS THE CORRECT FORMULA TO FIND OUT THE PROBABILITY that they will answer EXACTLY 40 questions correctly?

• ₅₀C₄₀ ( 0.40 )¹⁰ ( 0.60 )⁴⁰

• ₅₀C₄₀ ( 0.40 )⁴⁰ ( 0.60 )¹⁰

• ₅₀C₁₀ ( 0.40 )¹⁰ ( 0.60 )⁴⁰

• ₅₀C₁₀ ( 0.40 )⁴⁰ ( 0.60 )¹⁰

Find the mean of a binomial distribution with n=80 and q=0.28

• 22.4

• 57.6

• 43.4

• 5.15

Find the standard deviation of a binomial distribution with n=50 and p=0.4 (Round to the nearest tenth)

• 4.2

• 3.5

• 12.0

• 6.2

A test consists of 300 true or false questions. If the student guesses on each question, what is the standard deviation of the number of correct answers?

• 15.81

• 75

• 8.66

• 11.18

In a recent survey, 75% of the community favored building a police substation in their neighborhood. If 20 citizens are chosen, what is the variance of the number favoring the substation?

• 1.94

• 1.34

• 18

• 3.75

Fifty-seven percent of families say that their children have an influence on their vacation plans. Consider a sample of nine families who are asked if their children influence their vacation plans. Find the probability of exactly 5 families who said that their children don't have an influence on their vacation plans.

• 19.6%

• 80.4%

• 26.9%

• 74%